Admittedly I've taken it apart, so I must've assembled it wrong. Before the tension was already low, but now it's basically unusable. I can't figure out what I did wrong, since the spring can only be mounted in one way. Is it worn out maybe? I fitted it in the correct slots in both parts.
I'm not familiar with that paritcular design, but presumably you need to take it apart, and - with the spring engaged -twist it backwards past the stop as you reassemble it, so it has some tension in it.
its old af, so possible some wear, but unlikely on the spring. the tension should be pushing the long arm / idler wheel clockwise, maybe you have got the spring caught or over tightened the main screw?
Why is my T5 chain tensioner like this:
... when it's supposed to be like this(?):
Admittedly I've taken it apart, so I must've assembled it wrong. Before the tension was already low, but now it's basically unusable. I can't figure out what I did wrong, since the spring can only be mounted in one way. Is it worn out maybe? I fitted it in the correct slots in both parts.